CN103698698A - Diagnostic method of electrical life of high-voltage circuit breaker based on fuzzy theory - Google Patents

Abstract

The invention discloses a diagnostic method of electrical life of a high-voltage circuit breaker based on a fuzzy theory, belonging to the field of online monitoring and failure diagnosis technologies of power equipment. The method comprises the steps of (1), listing factors comprising switch abrasion, time parameter, average opening and closing speed and contact resistance into a factor set as diagnosis factors to determine a diagnosis language set; (2), determining a weight set, namely determining weight of the factors by using an analytic hierarchy process; (3), determining a membership function and a relational matrix; and (4), processing a fuzzy operator and an evaluation index. According to the method, the fuzzy theory is applied to the electric life diagnosis of the high-voltage circuit breaker; the factors such as the switch abrasion, the time parameter, the average opening and closing speed and the contact resistance and the like which reflect the electric life of the circuit breaker are taken into account; a diagnosis index system of the electric life of the circuit breaker is built; a plurality of failure diagnosis sample libraries are not required in the diagnosis method of the electric life of the circuit breaker; the method is easy to program and capable of quickly and accurately diagnosing the electric life of the circuit breaker.

Description

A kind of primary cut-out electric life diagnostic method based on fuzzy theory

Technical field

The invention belongs to electrical equipment online supervision and fault diagnosis technology field, be specifically related to a kind of primary cut-out electric life diagnostic method based on fuzzy theory.

Background technology

Along with society and economy is fast-developing, the status of electric system in national economy is increasingly important.Along with the raising of electric pressure and the increase of installed capacity, user is more and more higher to the requirement of power supply quality and power supply reliability, and this has proposed requirements at the higher level to power equipment monitoring and diagnosis technology.Primary cut-out is most important control and protection equipment in electric system, can carry at the appointed time under normal circumstances, cut-offs, close normal and fault current.The reliability service of primary cut-out is most important to the safety and stability of electric system.

Development along with technology such as the progress of electronic technology and sensor technology, optical fiber technology, computer technology, information processings, and the further investigation of failure mechanism, characteristic signal extracting method, make on-line monitoring and fault diagonosing technology progressively enter practical stage.The task of Fault Diagnosis for HV Circuit Breakers is according to the on-line monitoring information at equipment, in conjunction with known architectural characteristic and parameter and environmental baseline, the history run of reference device, determines character, degree, classification and the position of equipment failure, the sign of clear failure, reason and development trend.

The intelligent algorithms such as current support vector machine, neural network have been widely used in the fault diagnosis of primary cut-out, still due to these methods, still have the limitation of self, the requirement that actual accuracy rate of diagnosis and diagnosis efficiency are still difficult to meet rig-site utilization.The method for diagnosing faults of take based on neural network is example, and the method needs a large amount of fault sample storehouses for neural metwork training, and neural network learning speed of convergence is slow, easily be absorbed in local minimum point, cause diagnosis efficiency low, diagnostic accuracy is poor, is difficult to meet the requirement of rig-site utilization.

Summary of the invention

In view of this, the object of the present invention is to provide a kind of primary cut-out electric life diagnostic method based on fuzzy theory, the method is applied to fuzzy theory in the electric life diagnosis of primary cut-out, the factors such as switch wearing and tearing, time parameter, average mark closing speed, contact resistance of reflection circuit breaker electrical endurance have been taken into full account, set up primary cut-out electric life diagnosis index system, and primary cut-out electric life is diagnosed.

For achieving the above object, the invention provides following technical scheme:

A kind of primary cut-out electric life diagnostic method based on fuzzy theory, comprise the following steps: step 1: list switch wearing and tearing, time parameter, average mark closing speed, contact resistance factor in set of factors, as diagnosis factor, determine diagnosis language collection, each factor diagnosis unification is made as:

V={V _i| i=1, the good (V of 2,3,4}={ ₁), general (V ₂), note (V ₃), warning (V ₄);

Step 2: determine weight sets, adopt analytical hierarchy process to determine each factor weight; Step 3: determine subordinate function and relational matrix; Step 4: carry out the processing of fuzzy operator and evaluation index.

Further, in step 1, switch wear factor is specifically divided into contact electrical wear, accumulative total access times, three factors of accumulative total lifespan; Time parameter is specifically divided into three-phase separating brake asynchrony and three-phase and lock asynchrony; 8 material elementses of above-mentioned material elements conduct diagnosis primary cut-out electric life together with average closing speed, average opening velocity, contact resistance.

Further, in step 3, each diagnosis factor signal is divided into level Four after obfuscation, a line of each factor homography, the corresponding matrix of each group factor.

Further, in step 3, according to the N of isolating switch _l-I _ccurve, the correspondence that can try to achieve arbitrary size dropout current Ic allows to cut-off several N _l, the relative electrical wear that corresponding single cut-offs is 1/N _l(be defined as Q _m), try to achieve ∑ Q _m, its electric life is just f (x)=∑ Q _m, ∑ Q _mbe the numeral between 0 to 1, directly as subordinate function x value.

Further, in step 3, minute, switching synchronization should meet following requirement: alternate combined floodgate is the same period ≯ 5ms not; Alternate separating brake is the same period ≯ 3ms not; The not same period ≯ 3ms closes a floodgate between each fracture of homophase; The separating brake same period ≯ 2ms not between each fracture of homophase, sets up the subordinate function of three-phase separating brake asynchrony and three-phase and lock asynchrony.

Further, in step 3, for average opening velocity and average closing speed, its Fuzzy Distribution on circuit-breaker status impact is expressed as with Gauss distribution function:

$f\left(x\right)=\exp [-{\left(\frac{x-a}{b}\right)}^2]$

In formula, the unit of x is m/s, the center that a is subordinate function, i.e. and the desired optimum velocity of isolating switch producer, the width that b is subordinate function, determines average opening velocity and the requirement of average closing speed according to producer.

Further, in step 3, by measuring deciliter process electric current of isolating switch, the analysis of voltage waveform, try to achieve the contact resistance of isolating switch; The contact resistance of monitoring breaker is understood contact burning or the abrasion condition of isolating switch, thus the life-span of the contact of prediction isolating switch; Contact resistance is excessive, reflects that the running status of isolating switch own is not good; Representative function for isolating switch impact is defined as:

$f\left(x\right)=\frac{170-x}{170}$

Obtain the subordinate function of circuit breaker contact persistence.

Further, in step 4, adopt weighted mean Fuzzy operator, by step 3 definite weight and relational matrix substitution following formula can obtain last diagnostic result afterwards, according to maximum membership grade principle, get in the corresponding V of maximal value _idiagnostic result as primary cut-out electric life.

In formula: be respectively switch wearing and tearing in primary cut-out electric life diagnosis index system, time parameter and the corresponding fuzzy relation matrix of other factors 3 large class index; A is the weight of switch wearing and tearing, time parameter and other factors 3 large class indexs; A ₁, A ₂, A ₃be respectively the weight of each sub-index under switch wearing and tearing, time parameter and the large class index of other factors 3.

Beneficial effect of the present invention is: primary cut-out electric life diagnostic method of the present invention does not need a large amount of fault diagnosis Sample Storehouses, is easy to programming and realizes, and can diagnose out the electric life of primary cut-out rapidly and accurately.

Accompanying drawing explanation

In order to make object of the present invention, technical scheme and beneficial effect clearer, the invention provides following accompanying drawing and describe:

Fig. 1 is primary cut-out electric life diagnosis index system;

Fig. 2 is the schematic flow sheet of the method for the invention.

Embodiment

Below in conjunction with accompanying drawing, the preferred embodiments of the present invention are described in detail.

The present invention is applied to fuzzy theory in the electric life diagnosis of primary cut-out, the factors such as switch wearing and tearing, time parameter, average mark closing speed, contact resistance of reflection circuit breaker electrical endurance have been considered, set up primary cut-out electric life diagnosis index system, proposed a kind of primary cut-out electric life diagnostic method based on fuzzy theory.

Fig. 2 is the schematic flow sheet of the method for the invention, as shown in the figure, primary cut-out electric life diagnostic method based on fuzzy theory of the present invention, comprise the following steps: 1) list switch wearing and tearing, time parameter, average mark closing speed, contact resistance factor in set of factors, as diagnosis factor, determine diagnosis language collection, each factor diagnosis unification be made as:

V={V _i| i=1, the good (V of 2,3,4}={ ₁), general (V ₂), note (V ₃), warning (V ₄);

2) determine weight sets, adopt analytical hierarchy process to determine each factor weight; 3) determine subordinate function and relational matrix; 4) carry out the processing of fuzzy operator and evaluation index.

The factor that affects primary cut-out electric life is a lot, considers integrality and convenience that some off-lines or online data are collected, lists principal element in set of factors in the present invention, and to be set be 8 ranks.The concrete classification situation of each factor as shown in Figure 1.

1) determine diagnosis language collection

Each factor diagnosis unification is made as:

V={V _i| i=1, the good (V of 2,3,4}={ ₁), general (V ₂), note (V ₃), warning (V ₄); (1)

In formula: the good stage, represent that primary cut-out electrical wear is little, stable work in work, fault possibility occurrence is extremely low; In the general stage, illustrate that isolating switch has moved a period of time, had certain electrical wear, and serviceability is also basicly stable, and fault possibility occurrence is low; In the attention stage, represent the existing wearing and tearing significantly of contact of isolating switch, and the possibility breaking down is than increasing to some extent in the past, but isolating switch integral working still can meet the requirement of electric system, does not need isolating switch to change; Alert phase, shows that primary cut-out integral working is not good enough, needs it to pay close attention in actual motion and preventive trial, and the possibility breaking down is very high, can consider isolating switch to change.

2) determine weight sets

Adopt analytical hierarchy process to determine weight:

A ₁=[0.7693,0.1467,0.0840]，A ₂=[0.35,0.65]，A ₃=[0.4434,0.3873,0.1692]，A=[0.6,0.2,0.2]。

3) determine subordinate function and relational matrix

Each diagnosis factor signal is divided into level Four after obfuscation, i.e. a line of each factor homography, the corresponding matrix of each group factor.The relational matrix that 3 factors of switch wearing and tearing form is in Table 1.

Table 1 is electrical wear degree, accumulative total open and close times subordinate function table relatively

Table 2 lifespan subordinate function table

(a) according to the N of isolating switch _l-I _ccurve, the correspondence that can try to achieve arbitrary size dropout current Ic allows to cut-off several N _l, the relative electrical wear that corresponding single cut-offs is 1/N _l(be defined as Q _m), try to achieve ∑ Q _m, its electric life is just f (x)=∑ Q _m, because ∑ Q _mbe the numeral between 0 to 1, directly as subordinate function x value.

As primary cut-out allows action frequency, be N time, generally get 3000 times.So its transfer function can be able to be made as:

$f\left(x\right)=\frac{n}{N},$ ? $f\left(x\right)=\frac{n}{3000}---\left(2\right)$

The isolating switch that is M for regulation lifespan, it is 20 years that ZN48A-40.5 isolating switch is got M.

If its functional form is:

$f\left(x\right)={\left(\frac{x}{M}\right)}^2,$ ? $f\left(x\right)={\left(\frac{x}{20}\right)}^2---\left(3\right)$

(b) the different phases of three-phase separating brake close a floodgate the different phases from three-phase

According in < < power equipment preventive trial rules > > (DL/T596-1996) time parameter about asynchronous regulation: " 1) minute, closing time should meet makers' regulation; 2) divide, switching synchronization should meet following requirement during as manufacturing plant's no standard, alternate combined floodgate is the same period ≯ 5ms not; Alternate separating brake is the same period ≯ 3ms not; The not same period ≯ 3ms closes a floodgate between each fracture of homophase; The separating brake same period ≯ 2ms not between each fracture of homophase." set up evaluation factor subordinate function as table 2.

Table 2 splitting or integrating lock not the same period subordinate function table

(c) average opening velocity and average closing speed

For average opening velocity and average closing speed, its Fuzzy Distribution on circuit-breaker status impact can be expressed as with Gauss distribution function:

$f\left(x\right)=\exp [-{\left(\frac{x-a}{b}\right)}^2]---\left(4\right)$

In formula, the unit of x is m/s, the center that a is subordinate function, i.e. and the desired optimum velocity of isolating switch producer, the width that b is subordinate function, determines average opening velocity and the requirement of average closing speed according to producer.As: the average separating brake rate request of ZN48A-40.5 isolating switch is 1.7 ± 0.3m/s, and it is 1.2 ± 0.3m/s that average closing speed requires, and may be defined as:

The subordinate function of setting up evaluation factor is as table 3:

The average opening velocity of table 3 and average closing speed subordinate function table

(d) contact resistance

By to measuring deciliter process electric current of isolating switch, the analysis of voltage waveform, can be in the hope of the major loop resistance of isolating switch.The major loop resistance of monitoring breaker can be understood contact burning or the abrasion condition of isolating switch, thereby can predict the life-span of the contact of isolating switch.The resistance of major loop is excessive, reflects that this life of isolating switch running status is not good.Loop resistance is excessive except causing isolating switch inner heat excessively to accelerate the oxidation of contact position, and serious meeting causes the damage of isolating switch itself.Representative function for isolating switch impact is defined as:

$f\left(x\right)=\frac{170-x}{170}---\left(5\right)$

So it is as shown in table 4 to obtain the subordinate function of isolating switch major loop resistance:

Table 4 major loop resistance subordinate function table

3) processing of fuzzy operator and evaluation index

Adopt weighted mean Fuzzy operator, weight and the relational matrix substitution formula (6) determined can be obtained to last diagnostic result.Afterwards, according to maximum membership grade principle, get in the corresponding V of maximal value _idiagnostic result as primary cut-out electric life.

Embodiment:

Certain ZN48A-40.5 isolating switch has been worked 11 years, and accumulative total is moved 662 times, and the relative electrical wear degree of contact is 0.46 as calculated, major loop resistance is 73 Ω, the different phase 1.7ms of three-phase separating brake, the different phase 1.2ms of three-phase combined floodgate, average opening velocity 1.3m/s, average closing speed 0.7m/s.

Determine fuzzy relation matrix:

${\tilde{R}}_1=\left[\begin{array}{cccc}0& 0.35& 0.65& 0\\ 0.9& 0.1& 0& 0\\ 0& 0.53& 0& 0\end{array}\right]{\tilde{R}}_2=\left[\begin{array}{cccc}0& 0& 0.2& 0.4\\ 0& 0& 0.8& 0\end{array}\right]$

${\tilde{R}}_3=\left[\begin{array}{cccc}0& 0& 0.23& 0.77\\ 0& 0& 0& 1\\ 0& 0.85& 0.15& 0\end{array}\right],$ Substitution scoring model formula, result of calculation.The weight substitution of having determined can be obtained to last diagnostic result $\tilde{B}=\left(\begin{array}{cccc}0.0792& 0.2258& 0.4435& 0.1737\end{array}\right),$ According to maximum membership grade principle, show that this circuit breaker electrical endurance is in " attention " rank, the possibility that expression isolating switch breaks down is larger, need to keep a close eye on, but isolating switch integral working still can meet the requirement of electric system.

Finally explanation is, above preferred embodiment is only unrestricted in order to technical scheme of the present invention to be described, although the present invention is described in detail by above preferred embodiment, but those skilled in the art are to be understood that, can to it, make various changes in the form and details, and not depart from the claims in the present invention book limited range.

Claims (8)

1. the primary cut-out electric life diagnostic method based on fuzzy theory, is characterized in that: comprise the following steps:

Step 1: list switch wearing and tearing, time parameter, average mark closing speed, contact resistance factor in set of factors, as diagnosis factor, determine diagnosis language collection, each factor diagnosis unification is made as:

V={V _i| i=1, the good (V of 2,3,4}={ ₁), general (V ₂), note (V ₃), warning (V ₄);

Step 2: determine weight sets, adopt analytical hierarchy process to determine each factor weight;

Step 3: determine subordinate function and relational matrix;

Step 4: carry out the processing of fuzzy operator and evaluation index.

2. the primary cut-out electric life diagnostic method based on fuzzy theory according to claim 1, is characterized in that: in step 1, switch wear factor is specifically divided into contact electrical wear, accumulative total access times, three factors of accumulative total lifespan; Time parameter is specifically divided into three-phase separating brake asynchrony and three-phase and lock asynchrony; 8 material elementses of above-mentioned material elements conduct diagnosis primary cut-out electric life together with average closing speed, average opening velocity, contact resistance.

3. the primary cut-out electric life diagnostic method based on fuzzy theory according to claim 2, it is characterized in that: in step 3, each diagnosis factor signal is divided into level Four after obfuscation, a line of each factor homography, the corresponding matrix of each group factor.

4. the primary cut-out electric life diagnostic method based on fuzzy theory according to claim 3, is characterized in that: in step 3, according to the N of isolating switch _l-I _ccurve, the correspondence that can try to achieve arbitrary size dropout current Ic allows to cut-off several N _l, the relative electrical wear that corresponding single cut-offs is 1/N _l(be defined as Q _m), try to achieve ∑ Q _m, its electric life is just f (x)=∑ Q _m, ∑ Q _mbe the numeral between 0 to 1, directly as subordinate function x value.

5. the primary cut-out electric life diagnostic method based on fuzzy theory according to claim 3, is characterized in that: in step 3, minute, switching synchronization should meet following requirement: alternate combined floodgate is the same period ≯ 5ms not; Alternate separating brake is the same period ≯ 3ms not; The not same period ≯ 3ms closes a floodgate between each fracture of homophase; The separating brake same period ≯ 2ms not between each fracture of homophase, sets up the subordinate function of three-phase separating brake asynchrony and three-phase and lock asynchrony.

6. the primary cut-out electric life diagnostic method based on fuzzy theory according to claim 3, it is characterized in that: in step 3, for average opening velocity and average closing speed, its Fuzzy Distribution on circuit-breaker status impact is expressed as with Gauss distribution function:

$f\left(x\right)=\exp [-{\left(\frac{x-a}{b}\right)}^2]$

In formula, the unit of x is m/s, the center that a is subordinate function, i.e. and the desired optimum velocity of isolating switch producer, the width that b is subordinate function, determines average opening velocity and the requirement of average closing speed according to producer.

7. the primary cut-out electric life diagnostic method based on fuzzy theory according to claim 3, is characterized in that: in step 3, by measuring deciliter process electric current of isolating switch, the analysis of voltage waveform, try to achieve the contact resistance of isolating switch; The contact resistance of monitoring breaker is understood contact burning or the abrasion condition of isolating switch, thus the life-span of the contact of prediction isolating switch; Contact resistance is excessive, reflects that the running status of isolating switch own is not good; Representative function for isolating switch impact is defined as:

$f\left(x\right)=\frac{170-x}{170}$

Obtain the subordinate function of circuit breaker contact persistence.

8. according to the primary cut-out electric life diagnostic method based on fuzzy theory described in any one in claim 1 to 7, it is characterized in that: in step 4, adopt weighted mean Fuzzy operator, by step 3 definite weight and relational matrix substitution following formula can obtain last diagnostic result afterwards, according to maximum membership grade principle, get in the corresponding V of maximal value _idiagnostic result as primary cut-out electric life.

In formula: be respectively switch wearing and tearing in primary cut-out electric life diagnosis index system, time parameter and the corresponding fuzzy relation matrix of other factors 3 large class index; A is the weight of switch wearing and tearing, time parameter and other factors 3 large class indexs; A ₁, A ₂, A ₃be respectively the weight of each sub-index under switch wearing and tearing, time parameter and the large class index of other factors 3.